Chassis dynamometers have become an essential tool for serious performance workshops - they enable 'before' and 'after' power runs, tuning for every last kilowatt as well as detailed faultfinding. One company has dominated the Australian chassis dyno market for several years but now there's a new player on the scene - the DynoLogic dyno...
The DynoLog dyno is a joint development between Simon Gischus of Nizpro and Andrew Elder of DynoLog software. Simon says "I'd been using a chassis dyno for ten years and I thought there must be a better way of doing things. I mean, cars are making more and more power and, because of that, the grip issue was getting worse and worse." There were also problems in regard to having the retarder hood poking above ground level and some shortcomings with existing software systems - Simon admits he's been 'spoilt' by using Andrew's fantastic DynoLog software system in his engine dyno facility.
"I guess the project came together when I approached Andrew - who'd already been doing software upgrades for other chassis dyno operators - and proposed that we put our own system together" tells Simon. "I wanted the new dyno to address the problems I'd found over the years and I also wanted it to be fairly mobile - something the big race teams could pack in a truck and take to each round."
One of the biggest differences between the DynoLogic dyno and other commercially available units is the size of the front roller - the drive roller that measures a vehicle's torque. Simon told AutoSpeed, "we use a 560mm diameter drive roller because the Earth is essentially one huge roller. The diameter and the curve is so large that the tyre is driving on effectively a flat surface; that gives great traction because the tyre is acting against a bigger roller area. There's a lot of argument about all this but, look - no matter what anyone tells you - big rollers are a good thing.
"The roller we use is actually 10mm thick industrial tube." continues Simon. "We could have gone for a bigger diameter once again, but we chose not to for political reasons more than anything else. Compared to what's already available locally, we've already made a fairly bold move to go as big as we have. The argument against a big roller has always been in regard to inertia, but we counter that with the software that Andrew's developed - it smooth and softens the data, without causing any real inaccuracies."
The front roller features milled grooves across its length, which are said to provide improved tyre grip. "We finalised having the grooves based on everything we've learnt in the past - they seemed to work well. We knew the trade-off would be noise, but - as it turns out - it's not been a huge factor. Of course, during a power run the noise of the engine far exceeds that of the roller."
Note that the rear roller functions as simply an "idler". Since it is only used to support the opposite side of the tyres, the rear roller is a relative small 280mm diameter and has no grooves.
As mentioned, one of the annoyances Simon had with his previous dyno was the location of the retarder - a hood poked up above ground level, which was easy to trip over and left no space to fit a flex pipe to a car with side-exit pipes. The only solution was to leave the car blowing hot exhaust gas and soot directly at the retarder. With the DynoLogic design, the retarder is situated in the middle between the front rollers and is connected by a double row chain on each side.
The 'entry level' DynoLogic chassis dyno uses a single retarder, which Simon is conservatively rating at 550kW. It's capable of handling more but 550kW at the wheels is as much as they've been able to test - this is, after all, a mid 9-second street car.... Interestingly, the retarder is cooled by a fan that's activated by a thermocouple - "you don't want to heat soak the hell out of the retarder and everything else when you switch it off after a run" says Simon.
"One problem at the moment is power rating a chassis dyno. People say they've got an 1100kW dyno but, please, bring me an 1100kW at the wheels car and we'll see how it goes. I know with ours when you've got a car running at 200km/h and 550kW, you can grab the speed controller and wind it right down and the engine goes brrrrrrrrr. It pulls the engine right down so, obviously, there's still a fair bit in reserve."
For higher power applications, an upgrade retarder - which has 50 percent more capacity and is being rated at 850kW - can fit into the dyno in place of the smaller retarder. The smaller version should have the capacity to cater for most operators, however.
Note that, while a single retarder is ample for most front or rear wheel drive configurations, two retarder units are required in all-wheel-drive versions of the DynoLogic dyno. Thanks to Andrew Elder's brilliant software, the operator also has the ability to measure the front-to-rear torque split of any AWD vehicle - but we'll come to that in Part Two...
Yet another benefit of the centrally located retarder is the opportunity to keep the dyno's overall width down. Simon says "We've made it wide enough so that we could just fit it in the back of transporters. I believe once someone like HRT takes one to the racetrack every race team will follow. It is pretty heavy at 1150 kilograms though.
"Using our entry-level retarder we can dyno a car at 300 km/h. You could grab something like a Dodge Viper and ramp it from 1000 rpm up to, you know, over 260 km/h. The problem with the other dynos is - because they run a small retarder - the rotating assembly is spinning too quickly at those sorts of road speeds. You can't to it. Instead, you're forced to do it in a lower gear - ala you make more torque and there's more chance of turning the tyres.
"People say how you can strap cars down, but with this dyno we don't have to strap anything down until we're running a car at about 280kW at the wheels. On our old dyno we had to start getting the ropes out and calling everyone in the workshop to come jump in the boot at about 170kW. We've never had to stick anyone in the boot at this stage - in second gear my kitted LS1 ute makes about 3000Nm at the rear wheels and you don't turn a tyre.
"In any case, I recommend tying a car down though. If I'm putting something really tough on I'll strap it on front and back. People ask me why - I had one guy drive a car on the dyno and it started to climb forward a bit. He crapped himself, jumped on the brake and zipped straight off the back of the dyno."
The whole dyno assembly is made from 10mm thick mild steel, which is professionally laser cut - "we built it very rigid, so everything would be okay if you dropped it while putting it in the back of a truck" says Simon. "As you can see with our jig, it all comes together beautifully - we build it all here to within 20-thousands of an inch. That's one thing we're very proud of - the accuracy of the build. The advantage for the user is - if you had to replace a part - you know the new one will fit straight in. It's like buying a factory mudguard for a production car.
"The steel shafts we use are all 2-inch - most of the other ones we've seen range from 1 ¼ to about 1 ½-inch." The bearings are quality Japanese products that are contained in off-the-shelf industrial carriers. There is a bearing at each end of all four rollers and there is one either side of the retarder - Simon says the bearing life shouldn't be a problem, because there are so many used and the roller speed is relatively low. Everything found inside is very strong - perfect for sustaining extended high-load tuning.
At 2400m wide and 625mm tall, the DynoLogic dyno can be installed in or above ground (using a large pair of ramps). "I would suggest putting it in the ground" says Simon. "The problem with mounting it above ground is space - it takes up a lot of the space workshop owners usually use to park their customers' cars at night. I understand some people renting premises don't want to dig the big hole, but - generally - the landlord will be happy enough that you fill the hole in when you leave. And, realistically, to get outside contractors to dig the hole is not that much dearer than the ramp kit you need if you're going to use it above ground. We've made our dyno so it will fit between the posts of a hoist; you just stick a flat lid over the dyno when you're working on the hoist and it doesn't take up any space. The lid hides the fact there's a dyno in the workshop.
"During development we've had four prototypes and spent over twelve months working with them. There were no mechanical problems with the early prototypes, we just come up with better ways of assembling it. The first one we did is the one I'm still using here - we've changed stuff like the end plates to make any necessary work in the field easier.
Today - with examples going out the door for external use - the dyno is sold as part of a complete package. Buyers receive the dyno unit, a full software system plus things like a stand-alone PC and monitor in a cabinet, auto-correcting weather station, quality ear muffs, 5-pin late-model Bosch Lambda measurement and a dyno fan (capable of 80km/h winds).
In Part Two we'll speak to the software guru - Andrew Elder - take look at some power graphs and find out about prices...
Contact:
Nizpro
+61 3 9761 1522
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